Automatic conveyer for chemical and electrochemical operations



Feb. 7, 1933. .w. F. HALL ,0

AUTOMATIC CONVEYER FOR CHEMICAL AND ELECTROCHEMICAL OPERATIONS Filed Dec. 26, 1951 a Sheets-Sheet 1 AUTOMATIC CONVEYER FOR CHEMICAL AND ELECTROCHEMICAL OPERATIONS Filed Ded. 25, v19:51 8 Sheets-She et 2 g a gmL- w is a r NYA a fi a E w x ga v w M Q M .v Q m] a Feb. 7, 1933. w E HALL' 1,896,079

AUTOMATIC CONVE YER FOR CHEMICAL AND ELECTROCHEMICAL OPERATIONS Filed Dec. 28, 1931 8 SheetsSheet I5 W. F. HALL,

AUTOMATIC CONVEYER FOR CHEMICAL AND ELECTROCHEMICAL OPERATIONS 8 Sheets-Sheet 4 Feb. 7, 1933.

Filed Dec. 26, 1951 INVENTOR m, F. mm

j Feb. 7, 1933. w. E. HALL.

Filed Dec. 26, 1931 v 8 Sheets-Sheet 5 W.1.F. HALL 1,896,079

Feb. 7, 1933. Y

AUTOMATIC couvzxaa won CHEMICAL AND EL cTfiocHEuIcAL OPERATIONS} 8 Shets-Sheet 6 Filed Dec. 26, 1931 Feb. 7, 1 933. 'w. HALL' 1,896,079

AUTOMATIC CONVEYER FOR CHEMICAL AND ELECTROCHEMICAL OPERATIONS Filed Dec. 26. 1951 s Sheets-Sheet 7 Feb. 7, 1933. v W. F HALL 1,896,079

AUTOMATIC couvmmn FOR CHEMICAL AND ELECTROCHEMICAL orzmmons Filed Dec. 26, 1951 s sheets-sheet 8' WNW IINVENTOR v41 1mm BY I H what-3% Patented Feb. 7, 1933 UNITED STATES PATENT OFFICE WESLEY F. HALL, OF MATAWAN, NEW JERSEY, ASSIGNOR TO HANSON-VAN WINKLE- MUNNING COMPANY, OF MATAWAN, NEW JERSEY, A CORPORATION OF NEW JERSEY AUTOMATIC CONVEYER FOR CHEMICAL AND ELECTROCITEMICAL OPERATIONS Application filed December 26, 1931.

This invention relates to automatic conveyers for articles upon which a long series of operations or treatments are to be performed for producing a finished product, or for preparing said articles for further operations or treatments to be performed thereon. My invention contemplates more especially a system of conveyors provided with demountable work-carriers suitably constructed to be transferred from one to another of said conveyors at certain stages in a predetermined sequence of operations or treatments, for the purpose of timing the several operations or treatments as well as regulating the duration of the time-periods involved in each.

The primary object of my invention is to provide an improved construction and arrangement of conveyers and accessories thereto whereby time, labor and expense may be economized by reducing the number of workcarriers required for a desired process of manufacture, and by reducing the idle periods for each of said work-holders.

Certain specific objects of my invention reside in the peculiar construction and arrangement of conveyor parts, work-holders, and electrolytic apparatus employed in the quantity production of articles such'as the automobile bumper bars referred to in the specification. I

In the drawings Figures 1 and 1 together constitute a side elevation of a machine constructed according to my invention for electroplating bumper bars for automobiles.

Figures 2 and 2 together constitute a top plan view of the same.

Figure 3 is an enlarged elevation-of loading end of the machine.

Figure 4 is a transverse section on an enlarged scale on the line 44 of Figure 1.

Figure 5 is a similar transverse section on an enlarged scale corresponding to the line 5-5 of Figure l I Figure 6 is an inside elevationof a portion of the loading end of the machine taken on the line 6-6 of Figure 3.

Figure 7 is a fragmentary side elevation of one of the transfer conveyors from the inside according to line 77 f F igu e 4.

the

Serial No. 583,325.

Figure 8 is a side elevation from the inside of a portion of the unloading end of the maelectrolytic apparatus in one ofthe tanks.

Figure 10 is an enlarged fragmentary sect1on of the same, parts being broken away and parts shown in elevation.

Figure 11 is an enlarged fragmentary section taken on the line 1111 of'Figure 9, parts being shown in elevation; and

Figure 12 is a top plan View of the electrolytic grids on a smaller scale than that used in Figure 9.

Referring more particularly to the drawings, the main frame of the machine comprises two laterally spaced series of uprights 1 connected longitudinally by top side rails 2 and transversely by cross bars 3. Mounted upon each of the uprights 1 is a transverse bracket 4. Mounted upon the inwardly presented ends of the transverse brackets 4 on each side of the main frame is a longitudinal track bar 5 of channeled cross-section. Mounted on the outwardly presented ends of said transverse brackets are cat-walks 6 1, 1, 2 and 2 there is a loading space A at the left end of the machine, which opens into one end of an open-ended trough-like hous-.

ing B for the spray-washing of articles to be treated. Arranged next to the open forward end of the housing B is an alkaline electric cleaner tank C. Next in order is a cold rinsing tank D, an acid pickling tank E, and a second cold rinsing tank F. N ext in the series is a nickel plating tank G. A cold rinsing tank H follows next in the series and is interposed between the nickel lating tank and an acid copper plating tank Arranged in sequence after the copper plating tank I are two cold rinsing tanks K and L followed by a nickel plating tank M. A cold rinsing tank N and a hot rinsing tank 0 are arranged next in series, while at the extreme right of Figure 1 is shown an unloading space P.

Referring now to Figure 1 of the drawings, an electric motor 8, which may be mounted in any suitable manner between two of the adjacent uprights 1, is connected by a sprocket chain 9 through a speed changer 9 to a main power shaft 10, which extends from one end of the machine to the other. As shown at the right end of Figure 1 and at the left in Figure 5, the main power shaft 10 is connected by a reduction gear 11 to a short connection shaft 12, said connection shaft being provided with a spur pinion 13 which meshes with a larger spur gear 14 carried by a short shaft 15 journaled in the end upright 1. The inner end of the shaft 15 carries a spur pinion 16 which meshes into a spur gear 17 keyed to a sprocket shaft 18, said sprocket shaft being journaled in the upright 1 and supported at its outer end by a bracket arm 19. Connecting the sprocket shaft 18 and a transverse carrier chain driving shaft 20, is a sprocket chain 21. As shown in Figures 2 and 8, the transverse shaft 20 carries laterally-spaced sprocket wheels 22 over which run endless sprocket chains 23 of the carrier conveyer now to be described. Presented inwardly from each of the track bars 5, as shown in Figure 5, and arranged between the upper and lower edges of said track bars, are structural sections 24 which form longitudinal grooves within which run the rollers 25 of the endlesschains 23. Each of the endless chains 23 extends rearwardly around one of the sprocket wheels 22,Yfrorn which it is inclined downwardly and forwardly and passed around a guide sprocket wheel 23. As shown in Figures 1, 1 6 and 8, said chain passes lengthwise of the machine and at the loading end moves under a guide sprocket 23 and thence upwardly to and around a sprocket wheel 23, from which it passes onto the loading end of the grooved track bar 24..

It will be understood from the foregoing description that the repeated reductions in speed of the transmission gears for supplying power to this endless conveyer, imparts a slow but continuous forward progress to the conveyer chains 23. Used in connection with this slow moving conveyer are a plurality of work-carrying devices of improved construction, said devices being shown best in Figures 9, 10 and 11.

An important feature of this improved construction resides in the provision for separately carrying current to or from the articles or groups of articles supported by the work-carriers, so as to avoid the necessity of conducting su'ch current through the main supporting members of the work-carriers, and to thus enable the use of steel, or similarly advantageous structural metal, without regard to its electrical conductivity. Some of the electrical or electrochemical treatments involve the use of quite heavy current, and where such current is to be supplied to a number of articles on the same carrier, the cross-section of the carrier would have to be out of all proportion to the requirements of mechanical strength andstiffness if it were required to carry the entire current supply to all the articles supported by it.

As shown in Figure 9, each of the workcarriers includes a hollow shaft or bar 26 which carries at its opposite ends pick-up collars 27, said collars being adapted to travel along just clear of the upper flanges of the channeled track bars 5 as the carriers are propelled forwardly through the machine. b'ecured to the hollow shaft or bar 26, adjacent to each of the outer ends thereof, is a carrier-locating cam block comprising a split hub portion 28 adapted to be clamped to the carrier bar 26 by means of a bolt 29, a central wedge-shaped projection 30 presented downwardly from the bar 26 and two oppositely arranged lugs 31 which form with the projection 30 laterally-spaced notches fitting over the upper edges of the connection links extending between adjacent rollers 25 of the conveyer chains. As shown best in Figure 11, the projection 30 is provided with beveled edges to adapt said projection to center the carrier bar with respect to adjacent rollers 25 as it is lowered into position on the conveyer, the weight of the carrier when deposited upon the chain being sustained by the engagement of the lugs 31 with the ends of the outer links, with the central projection 30 clear of the rollers 25.

Arranged at spaced intervals along the carrier bar 26 are a plurality of depending work supports or hangers 32, which are provided with split hubs 33 bolted to the bar 26 by screws 34. Each of the hangers 32 is provided at its lower end with a button head 35, between which and the hanger shank is provided a circular groove adapted to receive the looped-up end 36 of a suspension link which in the present embodiment of my invention has been suitably constructed to suspend two oppositely arranged bumper bars 37, such as are employed on the ends of automobiles. The lateral spacing of the hangers 32 is such as to adapt the bumper bars to be lowered into a tank between adjacently disposed anode and cathode terminals of an electrolytic apparatus, and to be moved longitudinally of said terminals and finally removed from the tank by an'upward displacement of the carrier bar. As shown in Figure 10, the split hubs of the hangers are insulated from the carrier bars 26 by means of an interposed layer 38 of insulation, so as to confine the electrolytic currents to the immediate vicinity of the several parts through which the current is intended to pass.

According to the embodiment of my invention shown, Figure 9 shows an electroplating tank 39 provided along its top edges with transverse bars 40, composed of or covered with insulating material, upon which is mounted an anode grid comprising, trans- Verse conductor 41 and longitudinal conductors 42. Arranged above the anode grid is a cathode grid comprising a transverse bar 43 and longitudinally arranged bars 44, which are insulated from the tank as well as from the anode grid described. The lateral spacing of the anode and cathode bars is such as to leave intermediate spacesinto which the bumper bars may be lowered, moved forwardly through the tank, and again elevated therefrom during the uniform forward movement of the conveyer described above. By means of this arrangement of the parts,

the duration of the electroplating treatment.

can be determined accurately by the length of the electrolytic tank and the distance traveled by the bars during their suspension therein.

Where the articles are to be anodically treated, as for example in electrolytic pickling or bright dipping, the upper grid will of course be suitably connected to become the anode and the lower grid will be suitably connected to constitute the cathode.

Suitable means for carrying the electrolytic current from the hangers 32 to the cathode grid, may be'provided as follows. Projecting laterally from each of the hangers 32 is a bracket 45 which, as shown best in' Figure 10, carries a vertically arranged'bolt 46. A connection plate or brush 47 is provided at one end with a hole loosely fitting the bolt 46, and is yieldably retained against the flange 45 of the bracket by means of a compression spring 48 which is interposed between said conducting plate and the upper end of the bolt 46. The outer end of each brush 47 is adapted to slidably engage and make contact with one of the cathode bars 44.

To minimize current load fluctuation, the several brushes of each carrier are caused to establish electrical contact with their respec tive grid bars successively, instead of simultaneously. This is readily accomplished by providing the grid bars with micarta strips 44, or the like, of differentlengths, so that the brushes will slide off of them one after another into contact with their grid bars as the carrier moves along. If desired, the currents may be successively interrupted b similar strips of insulation 44 at the end of the treatment,

By an inspection of Figures 1 and 1, it will be noted that the path of the slow but continuous forward movement of the carrier bars 26, is arranged a short distance above the common plane of the successive tanks C, D, E, F, G, H, I, K, L, M, N and 0. Suitable means for transferring the carrier bars with their depending work from each tank to the one next in order, may be provided as follows.

Transfer convey ere As shown in Figure 4, the main power shaft 10 iscoupled by a reduction gear 49 to one end of a transverse shaft 50 which is journaled at opposite ends in the'laterally-spaced side frames. Keyed to the transverse shaft 50 are laterally-spaced sprocket wheels 51 which drive endless sprocket chains 52, each of said sprocket chains being mounted above on'a large sprocket wheel 53, which is journaled upon a stud 54 mounted in the adjacent upright 1, as clearly shown in Figure 7. The sprocket chains 52 thus run at relatively high speed around the lower and upper sprocket wheels 51 and 53., The upwardly and downwardly moving runs of each sprocket chain are spaced by separate guide sprockets 55 journaled on studs 56, the studs 56 of each of the transfer conveyers' being mounted in laterally-spaced side beams 57 of channeled cross-section. As clearly shown in Figures 4, 7 and 9, the sprocket chains 52 carry depending socket arms 58, or buckets,

which are pivotally suspended by studs 59 which project inwardly from the endless chains 52. These depending socket arms or buckets project into the vertical planes of the collars 27 on the ends of the carrier bars 26, the horizontal flanges of the channels 5 being cut away in the up and down paths of these socket arms to admit of their travel. As the socket arms 58 move upwardly from the lower sprocket wheel 51 and outwardly with respect thereto, the oppositely-arranged socket arms 58 are simultaneously brought into position to intercept the collars 27, 27,

on opposite ends of the carrier bar 26 at the instant that said carrier .bar moves over the cut away portion of the channels 5 into the path of the socket arms 58. Said carrier bar is thus lifted from its position on the slow moving honizontal conveyer and moves rapidly upwardly around the sprocket wheels 53 at the top and downwardly on the descending side of the transfer conveyer until it again reaches the path of the slow moving horizontal conveyer at the instant that the interroller space of said horizontal conveyer is suitably positioned to intercept the downward movement of the collars 27. of this automatic action is to lift the bumper bars 37 from one tank, after a predetermined y period of submergence therein, over into the next tank, in the order of its progress, in a forward direction. The transfer conveyer just described is duplicated at several points along the machine, as indicated on Figures 1 and 1 by the reference characters 52.

Quick return conveyer Referring now to Figures 3' and 6, it will The result 62 on one end of a cross-shaft 63, which is journaled in the opposite side frames of the machine. Keyed to the cross-shaft 63 are laterally-spaced sprocket wheels 64:: which ,drive endless chains 65. The gear reduction and the proportions of the upper and lower sprockets of the drive chain 61, as well as the size of the drive sprocket (ii, are so calculated as to give the quick return chains 65 a much higher running velocity than that of the conveyer chains 23. Said chains 65 pass upwardly over guide sprockets 66 Figure 6) and forwardly to and around guide sprockets 67 (Figure 8) at the unloading end of the machine. Moving upwardly from the guide sprockets 67, said sprocket chains 65 pass upwardly to laterally-spaced guide sprockets 68 and move in a substantially horizontal plane near the top of the apparatus back to the loading end of the machine and thence downwardly around laterallyspaced guide sprockets 60 (Figure 6). At

spaced intervals along the sprocket chains 65, inwardly-presented studs 70 are arranged to pivotally support suitable depending socket arms or buckets 71 which, at the unloading end of the machine, come up under the collars 27 of the carrier bars 26 just as said collars enter the upward paths of the buckets 71. The carrier bars 26 are thus lifted from the horizontal conveyer and moved at relatively high velocity upwardly and rearwardly to the loading end of the machine, Where said carrier bars are again intercepted by the loading end of the slow moving horizontal conveyer.

The apparatus described automaticallv feeds the carrier bars from one operation or station to another until, as each arrives at the end of the machine, it is lifted off the slowly moving conveyer and at a much higher rate of travel is returned to the starting point and again deposited on the slow conveyer. Where the apparatus is to be tended by hand, one operator or group of operators will be stationed at the loading end and hang the work-pieces on the hangers as each hanger is redeposited on the slowly moving conveyer. At the discharge or unloading end of the apparatus another operator or group of operators may be stationed to remove the finished work-pieces from their hangers prior to the lifting of the hangers from the slowly moving conveyer in preparation for the quick return to the loading end.

The particular operations performed on the work-pieces during their travel through themachine are not in themselves essential to the present invention, but may be quite varied. Some tanks may contain chemicals which operate on the Work-pieces independently of any current supply or electrochemical action; others may contain rinse water, soaping solutions, lacquering or enameling baths, or the like; while still others may perform electrochemical operations such as elec troplating or electrolytic pickling or bright dipping. Wherever electric current is required, it will be understood that the anode and cathode grills, such as described in connection with Figures 9 and 12, may be employed.

By maintaining the slowly moving conveyer system in a constant speed ratio to the rate of travel of the transfer and quick return systems, accurate registration of the lifting buckets with respect to the positions of the carrier bars may be maintained at all times. The timing of the difierent treatments to whi h the work-pieces are to be sub jected is, of course, automatically dependent upon the distance through which the workpiees travel in the respective tanks or stations. The particular voltage impressed between the work-pieces and the opposite electrodes in any electrolytic tank, may be quite independent of the voltages impressed in any or all of the other electrolytic tanks, due to the local connections in each tank being independent, if desired, of those in other tanks. Heating or cooling may be employed in one or more of the tanks where necessary, if desired.

In many of the full-automatic plating machines, the number of operations is so great, and the total time of treatment so long, that the number of hangers with which the machine must be equipped represents a substantial portion of the total cost of the machine. Where the hangers, upon being discharged from the last operation, are returned to the loading end at the same rate of speed as that at which they have been fed through the apparatus, there are substantially as many idle hangers on their way back to the loading end as there are hangers in active service. By maintaining a separate and distinct return system operable at a much higher speed than would be suitable for the carrying of the work-pieces through the various operations to be performed on them, the number of idle carriers is correspondingly re duced, and hence the total number of carriers with which the machine must be equipped to perform a given series of operations is reduced, and substantial economy secured.

I claim 1. Apparatus of the character described, comprising in combination a series of workstations for the performance of operations upon work-pieces to be conveyed therethrough, a conveyer traversing the series of work-stations, work-piece hangers removably mountable on said conveyer, and means operating in timed relation with said conveyer but at a higher rate of travel for removing each hanger from said conveyer at a point leaving the series of work-stations and returning it to said conveyer at a' point ap proaching said series of work-stations.

veyer traversing the series of work-stations,

work-piece hangers removably mountable on said conveyer, transfer mechanism for removing each hanger from said conve v 'er, at a point leaving each work-station and returning it to said conveyer at a point entering the succeeding work-station, and quick return means for removing each hanger from said conveyer at a point leaving the last workstation and returning it to said conveyer at a point approaching the first work-station, said transfer mechanism and said quick return means being interconnected with said conveyer to operate in timed relation therewith but at a higher rate of travel.

3. Apparatus of the character described, comprising in combination a loading station, an unloading station, a series of work-stations for the performance of operations upon workpieces conveyed thereto between said loading station and said unloading station, a conveyer successively traversing the loading station, work-stations and unloading station, workpiece hangers removably mountable on said conveyer, andmeans operating in timed relation with said conveyer but at a higher raie of travel for removing each hanger from sa1d conveyer at the unloading station and returning it to said conveyer at the loading station.

4. Apparatus of the character described, comprising in combination a loading station, an unloading station, a seriesof work-stations for the performance of operations upon workpieces conveyed thereto between said loading station and said unloading station, a conveyer traversing successively the loading station, the series of work-stations, and the unloading station, work-piece hangers removably mountable on said conveyer, a rapid transfer mechanism operating between each work-station and the next succeeding station in the series, to remove each hanger from the conveyer as it leaves one work-station and return it to theconveyer as it enters the succeeding station, and a quick return means for removing each hanger from said conveyer at the unloading station and returning it to said conveyer at the loading station, said rapid transfer mechanism and the said quick return means being interconnected with said conveyer to operate in timed relation therewith but at a higher rate of travel.

5. Apparatus of the character described, comprising in combination an endless workconveyer, a plurality of work-carriers removably mountable on said work-conveyer, work-treating units disposed along the path of said work-conveyer, an endless return conveyer crossing said work-conveyer at points preceding and succeeding said Work-treating units, means carried by said return conveyer for removing work-carriers from said workconveyer at the point of crossing succeeding said work-treating units and replacing them thereon at the point of crossing preceding said work-treating units, a common driving means for said work-conveyer and returnconveyer, and interconnections between said conveyors and said driving means, for maintaining the speed of said return-conveyer higher than but in constant ratio to the speed of said work-conveyer.

6. Apparatus of the character described, comprising in combination an endless workconveyer, a plurality of, work-carriers removably mountable on said work-conveyer, work-treating units disposed along the path' of said work-conveyer, an endless return conveyer crossing said work-conveyer upwardly at a point succeeding and downwardly at a point preceding said work-treating units, means carried by said return conveyer for lifting work-carriers from said work-conveyer at the point of crossing succeeding said work-treating units and replacing them thereon at the point of'crossing preceding said work-treating units, a common driving means for said work-conveyer and return-conveyer, and 1nterconnect1ons between said conveyers and sald dllVlIlg means, for mamtalning the speed of said return-conveyer higher than but in constant ratio to the speed of said work-conveyer.

7. In mechanism of the character described, the combination with a series of work-carriers, of a conveyer for releasably engaging said work-carriers and moving them from an initial position through progressive stages of movement for imparting successive treatments to the work carried thereby, means movable at a faster rate of speed than said conveyer and in a direction opposite thereto for returning said workcarriers to initial position.

8. Apparatus of the character described,

comprising in combination an electrolytic tank, a plurality of anode contact bars and cathode contact bars extending in parallel directions over said tank, a conveyer traversing-said tank in the direction of said contact bars, a'work-carrier having a plurality of work-suspension members insulated therefrom and spaced apart thereon to suspend Work-pieces in the lanes between the anode and cathode contact bars, brushes carried by said insulated work-suspension members in position .to engage the contact bars of one polarity, electrodes suspended from the contact bars of the other polarity, insulation sections extending different distances along the surface at one end of the contact bars with which said brushes are to make contact, and means for placing said work-carrier on said conveyer with the brushes on the insulation sections for movement by said conveyer into successive electrical contact with the respective contact bars.

9. In mechanism of the character described, the combination with an extended series of tanks, of a work-carrier conveyer movable at uniform speed over said tanks in succession, work-carriers detachably mountable on said work-carrier conveyer for suspending the work in said tanks, a transfer conveyer adapted to separately engage said work-carriers and transfer them from one of said tanks to another, anode and cathode contact bars disposed in said tanks parallel to the direction of movement of the workcarriers therethrough, electrodes suspended from one of said contact bars, means carried by said work-suspension means for slidably engaging the other of said contact bars, and a quick return conveyer adapted to lift the work-carriers from said work-carrier conveyer and return them to initial position.

10. In mechanism of the character described, the combination with an extended series of tanks, of work-carriers provided with insulated means to suspend the work in said tanks, a conveyer adapted to move said work-carriers in a series over said tanks, means for separately engaging said workcarriers for transferring them successively from a position over one tank to a position over another tank, anode and cathode contact bars arranged parallel to the direction of movement of the work-carriers through one or more of said tanks, electrodes suspended from the contact bars of one polarity, means carried by and electrically connected to the insulated work-suspension means for slidably engaging the contactv bars of the other polarity, and a quick-return conveyer movable upwardly across the path of said workcarriers at an unloading position and downwardly back to the loading position thereof for returning said work-carriers to loading position.

11. In mechanism of the character described, the combination with an extended series of electrolytic tanks, of an endless con-' veyer movable continuously at a uniform rate of speed above said tanks, workcarriers adapted to be detachably mounted on said endless coveyer at a loading position, said work-carriers being provided with insulated work-suspension means, electrolytic apparatus in said electrolytic tanks including circuit connections for forming electrolytic circuits including the insulated work-suspension means and work suspended therefrom, a transfer conveyer arranged between each pair of successive electrolytic tanks, said transfer conveyers being adapted to elevate the work-carrier with the work from one tank and to lower it into the next tank, and a quick 'return-conveyer adapted to intercept the work-carriers at an unloading position and return them to the loading position on said endless conveyer.

12. In mechanism of the character described, the combination with an extended series of tanks, of an endless slow-moving conveyer movable over the tops of said tanks, work-carriers detachably mounted on said slow-moving endless conveyer, vertical quickaction conveyers operating between successive tanks for moving said work-carriers vertically to transfer the work from one tank to another, electrolytic circuits having contacts adapted to be broken in one'tank by the upward movements of a work-carrier and made in the next tank by the downward movement of the Work-carrier, and an endless quick return-conveyer movable upwardly past said slow-moving endless conveyer at an unloading position and downwardly past said slowmoving conveyer at a loading position, said quick return-conveyer being provided with means for detachably engaging said workcarriers to return them to the loading position on the slow-moving conveyer.

13. Apparatus of the character described,

comprising in combination an electrolytic tank, a work-conveyer traversing said tank, a plurality of contact rails extending over said tank in the direction of travel of said workcon-veyer, electrodes immersed in said tank, an electric circuit of which one side is connected to said electrodes and the other side to said contact rails, a work-carrier mountable on said Work-conveyer and having insulated work-hangers provided with contacts adapted to move along said contact rails while the carrier is mounted on said conveyer, means for automatically mounting said carrier on said conveyer, and means for insulating said hanger contacts from said contact rails for different distances along the different rails to prevent simultaneous closing of the circuits therethrough.

14. Apparatus of the character described, comprising in combination anelectrolytic tank, a work-conveyer traversing said tank, a plurality of contact rails' extending over said tank in the direction of travel of said conveyer, electrodes immersed in said tank, an electric circuit of which one side is connected to said electrodes and the other side to said contact rails, a work-carrier removably mountable on said conveyer and having insulated work-hangers provided with contacts adapted to move along said contact rails while the carrier is mounted on said conveyer, means for automatically mounting said carrier on said conveyer, and means for insulating said hanger contacts from said contact rails for different distancesalong the different rails at each end thereof to prevent simultaneous closing or opening'of the circuits therethrough.

' WESLEY F. HALL. 

